Call it post-jazz: the category-defying dance form finds common ground in energy and emotion.

A pool of light illuminates a barefoot dancer striking a defiant pose, her scarlet skirt whipping around her. A driving, percussive score intensifies as she and bet fellow dancers savagely thrust themselves into and out of their partners' grasps in a modern, frenetic take on a primitive mating ritual. The curtain rises again on a different work, and a recorded voice booms, "This is The Krew." The audience hoots and claps along to songs by Janet Jackson and J. Lo as the dancers ham it up in a street dance medley brimming with attitude and funk. When the lights come up yet again, two female dancers in white bow ties and gloves are high-kicking across the stage to "Sing, Sing, Sing," their stylized leaps and turns cast in giant shadows on the wall behind them.

This motley selection of dances represents only a small scrap of the styles showcased under the banner of "jazz dance" last year in Buffalo at the 2003 Jazz Dance World Congress, where the performances ranged from modern dance and hip bop to Broadway-style showmanship and martial arts-flavored acrobatics. The hodgepodge seems to confirm that a tidy definition of jazz dance remains as elusive today as it was fifty years ago, when the form first began to emerge on the concert stage. That the pieces fit together in spite of their aesthetic differences suggests that the unifying element may not be a common technique or vocabulary, but rather the feeling it inspires.

"I think jazz dance is an innately emotional form because the music is emotional," says Pennsylvania-based choreographer/dancer Cathy Young. "There's passion and heart and soul in the music. The audience feels it, and there is a visceral response."

Like jazz music, jazz dance was born in bars and nightclubs and grew up on the vaudeville circuit--not on the concert stages like ballet and modern dance. Jazz dancers were not "artists," but "entertainers" whose acts were designed to please crowds. Jazz dance was more showbiz than high art--a staple of variety shows, movies, Broadway and TV.

"Jazz has always been the black sheep of the dance family," says Derryl Yeager, artistic director of Odyssey Dance Theatre of Utah, which performed The Krew. "I think in some ways that's because of jazz trying to find its voice in a concert setting."

Today's jazz choreographers believe that art and entertainment don't have to be mutually exclusive, but how they reconcile the two differs in the voices they choose. Some believe in staying true to the roots of jazz by using only jazz music and drawing from the vernacular jazz movements that developed in the first half of the twentieth century. Others feel that is too limiting a definition and prefer to blend aspects of modern, ballet, and other dance forms. There are some who so disdain jazz's association with flashy, MTV-style dance that they hesitate to even use the word "jazz" to describe themselves.

"If I say that what I do is jazz, then it sounds like I'm only doing one thing, and it sounds borderline commercial," says Ronen Koresh, artistic director of the Philadelphia-based Koresh Dance Company. Koresh's intense, dramatic style blends elements of modern, jazz, and folk dance. (See "The Electric Company," page 32.) "But I believe that the basis of my ability to be creative is the fact that I was a jazz dancer."

Other choreographers, such as Frank Chaves of River North Chicago and Yeager of Odyssey Dance Theatre, are unapologetic about blending commercial or theatrical aspects into their repertoires. Chavez says the defining aspects of his company are accessibility and entertainment. "I really care about involving our audience," he says. "There are companies that will choreograph only for art's sake, whereas we still keep our audiences in mind. Yon will not only see River North, you will feel River North." Yeager's pieces incorporate theatrical elements such as oversized, cartoonish props in the Peter Gabriel medley Sledgehammer and water pouring down on the dancers in the Odyssey's lyrical signature piece, Rain.

Reginald Ray-Savage, artistic director of the Oakland, California-based Savage Jazz Dance Company, says jazz needs no adornment other than live jazz music in order to get the feeling across. He finds it troubling that many jazz dance companies use jazz music infrequently or not at all. He says he detects "a certain amount of racism in it," adding: "Balanchine is not who he is without Stravinsky; Petipa is not Petipa without Tchaikovsky. Why do the rules get changed when it comes to jazz? Is it because the music is so black?"

Like Savage, Vicki Adams Willis, artistic director of the Calgary, Alberta-based Decidedly Jazz Danceworks, insists that jazz dance can't exist without jazz music. As for jazzy pieces set to pop music, she says, "I just wish it wasn't called jazz. Pop music resonates through the body in a very different way, and the resulting movement aesthetic is very different from what would happen if you danced to jazz and honored the music."

Billy Siegenfeld, artistic director of Chicago-based Jump Rhythm Jazz Project, believes that jazz music and dance grew out of the natural urge to create rhythm. Siegenfeld, who describes his rhythm-based technique as "tap-dancing through the body," says jazz is a rich language that needs no translation, "There are lots of people who feel that all that jazz expresses is being hot, or being downhearted from a lost love affair," says Siegenfeld. "I feel that jazz is capable of expressing any emotional state."

Perhaps what makes jazz accessible to audiences and yet somewhat problematic for artists is its connection with sex and sensuality. The word itself derives from "jass," a slang word for sex that developed in early twentieth-century New Orleans. But the modern association probably has more to do with Bob Fosse's stylization of the bump-and-grind. Today's choreographers respect Fosse and embrace jazz's sensuality, but they don't want to fuel the perception that jazz has a one-track mind. "I'm not out to seduce the audience; I'm out to engage them in other ways," says Danny Buraczeski, whose Minneapolis-based JAZZDANCE company uses jazz music as a springboard for its modern-flavored jazz works. "There's so much more about the human condition to explore."

Cathy Young suggests that Western culture's mistrust of the body leads to misconceptions about jazz dance. "Because it's rooted in the body and there's a real gut-level response to it, people feel there's not a sufficient level of intellect to put it up there with ballet and modern dance." Young, who studied postmodern dance, laughingly calls her choreography "post-jazz." "There is a lot of fluidity and release within the movement," she explains. "I work with swing and energy flow, which I think is very aligned to jazz. It's that concept of what's happening between the beats."

Whether through "jazzy" movement or a blend of ballet and modem, whether with extravagant sets or a bare stage with barefoot dancers, you may not recognize jazz dance when you see it, but you'll know it when you feel it. "Everything we do--it must have feeling, it must have soul," says Nan Giordano, artistic director of Gus Giordano Jazz Dance Chicago and the Jazz Dance World Congress. "You don't have to be a dance lover. I want people to walk away feeling energized, feeling excitement--just feeling."

Michelle Vellucci is a Manhattan-based dance writer and book critic.